Standardized testing (ASVAB) to gauge what job family you will be assigned to, character interview to determine criminal history if any, as well suitability and eligibility for a security clearance. Additionally, there is a drug screen, medical exam, background check, interviews of family, friends, and associates.
I applied through a recruiter. The process took 3 days. I interviewed at US Marine Corps (Twentynine Palms, CA) in Mar 2020
Interview
They will seek you out if you're interested and talk to you about the benefits. It's not too hard, as long as you pass your ASVAB. It could have been better.
Interview questions [1]
Question 1
Can you pick three works from this stack of words?
Screened by OSO and his/her team. They will basically test if you are serious about earning a commission and if you aren’t, they won’t be looking to spend the time and effort on recruiting you.